Display screen or portion thereof with a graphical user interface for a therapy device



FIG. 1 is a front view of a display screen or portion thereof with a graphical user interface for a therapy device, showing a first embodiment thereof; and,

FIG. 2 is a second embodiment thereof.

The outermost broken line showing the display screen or portion thereof defines the bounds of the claimed design and forms no part thereof. The remaining broken lines show portions of the graphical user interface. No subject matter depicted in any of the aforementioned broken lines forms part of the claimed design. 

CLAIM The ornamental design for a display screen or portion thereof with a graphical user interface for a therapy device, as shown and described. 